Confinement of electromagnetic energy as it propagates along a fiber is useful for a variety of technologies including, but not limited to, communications, detectors, sensors and experimentation. One mechanism uses total internal reflection to confine the electromagnetic waves to the fiber. Total internal reflection can be accomplished by using materials with different kinds of refractive indices. In particular, a central portion of the fiber can be constructed out of a material with a higher index of refraction (“index”) than a surrounding material (or cladding material). The electromagnetic energy is reflected at the boundary between these two materials. These and other matters have presented challenges to guiding waves, as may be implemented for a variety of applications.